The word for today is…
fortitude (noun) – Strength of mind that allows one to endure pain or adversity with courage.
Source : The Free Dictionary
Etymology : Fortitude comes from the Latin word fortis, meaning “strong,” and in English it has always been used primarily to describe strength of mind. For a time, the word was also used to mean “physical strength”; William Shakespeare used that sense in Henry VI, Part 1: “Coward of France! How much he wrongs his fame / Despairing of his own arm’s fortitude.” But despite use by the Bard, that second sense languished and is now considered obsolete.